1. Field of the Invention
This invention provides a microswitch which can be switched by loading a projection of a push lever projecting outside a case with external force or releasing the external force therefrom and which has general-purpose properties for an operation, a detection and so on of a wide variety of apparatuses.
2. Description of the Prior Art
A conventional microswitch which has been generally and widely used is constructed so that one end of a contact spring piece comprising a tension member and a compression member is fixed in a small box-shaped case (common terminal) and the other end is provided with a movable contact, said movable contact being provided opposite a fixed contact (terminal) (separately therefrom or coming into contact therewith), the above-described contact spring piece is pressed and inverted by pressing and descending an actuator, for example, a press button, the contact spring piece is reversed and inverted (snap action) at a given pressing point and contact of the movable contact with the fixed spring (ON) or separation of the movable contact from the fixed spring (OFF) is performed instantly. However, in case of the above-described conventional microswitch, not only has it been difficult to produce the contact spring piece comprising the tension member and the compression member precisely without scatter in each switch for manufacturing processing technique, material and so on with miniaturization of the switch, but also the precision in mounting technique for mounting the microswitch to a case has been at the end of its limitation and, particularly, it has not been possible to correspond to the recent super-miniaturization, for example, each dimension of longitude, side and height is proximately 10 mm, and there has been a problem that cost rises inevitably because of miniaturization and improvement in precision.
Furthermore, since the contact (ON) pressure of the movable contact with fixed contact which are important points for a switch operation is only spring pressure of a small contact spring piece, there occurs scatter in the contact pressure for every switch operation, thereby making the switch performance unstable. Also, there has been a problem that the switch performance deteriorates because of dirt on a contact part after long-term use, repeated use and so on.